Shaker core



FIG. 1 is a perspective view of a new design for a shaker core.

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof; and,

FIG. 5 is a bottom view thereof.

The broken line showing of portions of the shaker core is included for the purpose of illustrating and forms no part of the claimed design. 

CLAIM The ornamental design for a shaker core, as shown and described. 